Synthesize of glycidoxy propyl trimethoxy silane-polyoxy propylene diamine as an anticratering agent for cathodic electrocoating

Cathodic electrocoating is a widely used technique for the application of anticorrosion primer in the automotive industry[1]. Many surface defects may appear in the coatings applied by electrodeposition coatings, one of the most important defects in automotive coatings is cratering.Cratering is small crater shaped depressions. Cratering results from a low surface tension contaminant which is on the substrate, in the coating, or which lands on the wet surface of a freshly applied film, some of the low surface tension contaminant dissolves in the film, as a result of marangoni effect, flow occur from the low surface tension parts to high surface tension parts of the film. However, evaporation of solvent causes an increase in viscosity which impedes flow leading to formation crater. As surface flow phenomena causes the crater defect, additives can be used to minimize cratering. Silicones or other surfactants are used as anticratering agents to eliminate cratering[2,3]. In the present work, glycidoxy propyl trimethoxy silane-polyoxy propylene diamine has been prepared as an anticratering agent for cathodic electrocoating.